Introduction: Sarcoidosis is a multisystemic granulomatous disorder characterized by multiple noncaseating granulomas involving intrathoracic lymph nodes and lung parenchyma. Recently, the use of anti-tumor necrosis factor alpha (anti-TNFα) agents has been introduced for therapy of chronic and refractory sarcoidosis with controversial results. Infliximab (Remicade) is a chimeric monoclonal antibody (mAb) that recognizes and binds TNFα, neutralizing its biological effects. In the present study, (99m)Tc labelled infliximab was used to study the expression of TNFα in sarcoid lesions and to evaluate its role as a predictive marker in response to therapy with Remicade.

Material and methods: A total of 10 patients with newly diagnosed sarcoidosis were enrolled together with 10 control patients affected by rheumatoid arthritis. All patients were studied by planar imaging of the chest with (99m)Tc-infliximab at 6 h and 24 h and total body [(18)F]-FDG PET/CT. Regions of interest were drawn over the lungs and the right arm and target-to-background ratios were analysed for (99m)Tc-infliximab. SUV mean and SUV max were calculated over lungs for FDG.

fig1: 99mTc-Infliximab scintigraphy of a sarcoidosis patient (patient 3/F) acquired at 6 h (anterior and posterior views (a)) and at 24 h (anterior and posterior views (b)) showing a moderate and diffuse uptake in the lung parenchyma. [18F]-FDG PET/CT images of the same patient showing a focal/hyleal uptake (coronal and transaxial sections (c)).

Mentions:
The qualitative analysis performed on PET/CT studies in lungs showed complete agreement with the staging previously made by pulmonologists according to radiological and biochemical findings (Figure 1). Furthermore, in 3/10 patients PET showed other extrapulmonary sites of disease, with involvement of axillary and abdominal-pelvic lymph nodes, not previously known, demonstrating its high sensitivity. The mean values ± SD of SUVmax⁡ obtained in patients with sarcoidosis were 4.43 ± 3.20 whereas in control subjects mean values ± SD of SUVmax⁡ were 1.18 ± 0.20 (P < 0.001). These data are an expression of inflammation involvement of lung parenchyma in patients with sarcoidosis. The values of SUVmax⁡ and SUVmean correlated perfectly; therefore for subsequent analysis only SUVmax⁡ will be reported even if also SUVmean has always been considered. Despite the higher values of SUVmax⁡ in patients with sarcoidosis with respect to controls, it was not possible to find a cut-off value that could allow the correlation of the extent of uptake in the lung parenchyma with the degree of alveolitis. It was not also possible to obtain a significant correlation between lymphocyte immune-phenotyping results of BAL (with particular reference to CD4+/CD8+ ratio) and the SUVmax⁡ values of patients with sarcoidosis. No correlation was also observed between SUVmax⁡ or SUVmean values and the CD4+/CD8+ ratio in blood.

fig1: 99mTc-Infliximab scintigraphy of a sarcoidosis patient (patient 3/F) acquired at 6 h (anterior and posterior views (a)) and at 24 h (anterior and posterior views (b)) showing a moderate and diffuse uptake in the lung parenchyma. [18F]-FDG PET/CT images of the same patient showing a focal/hyleal uptake (coronal and transaxial sections (c)).

Mentions:
The qualitative analysis performed on PET/CT studies in lungs showed complete agreement with the staging previously made by pulmonologists according to radiological and biochemical findings (Figure 1). Furthermore, in 3/10 patients PET showed other extrapulmonary sites of disease, with involvement of axillary and abdominal-pelvic lymph nodes, not previously known, demonstrating its high sensitivity. The mean values ± SD of SUVmax⁡ obtained in patients with sarcoidosis were 4.43 ± 3.20 whereas in control subjects mean values ± SD of SUVmax⁡ were 1.18 ± 0.20 (P < 0.001). These data are an expression of inflammation involvement of lung parenchyma in patients with sarcoidosis. The values of SUVmax⁡ and SUVmean correlated perfectly; therefore for subsequent analysis only SUVmax⁡ will be reported even if also SUVmean has always been considered. Despite the higher values of SUVmax⁡ in patients with sarcoidosis with respect to controls, it was not possible to find a cut-off value that could allow the correlation of the extent of uptake in the lung parenchyma with the degree of alveolitis. It was not also possible to obtain a significant correlation between lymphocyte immune-phenotyping results of BAL (with particular reference to CD4+/CD8+ ratio) and the SUVmax⁡ values of patients with sarcoidosis. No correlation was also observed between SUVmax⁡ or SUVmean values and the CD4+/CD8+ ratio in blood.

Introduction: Sarcoidosis is a multisystemic granulomatous disorder characterized by multiple noncaseating granulomas involving intrathoracic lymph nodes and lung parenchyma. Recently, the use of anti-tumor necrosis factor alpha (anti-TNFα) agents has been introduced for therapy of chronic and refractory sarcoidosis with controversial results. Infliximab (Remicade) is a chimeric monoclonal antibody (mAb) that recognizes and binds TNFα, neutralizing its biological effects. In the present study, (99m)Tc labelled infliximab was used to study the expression of TNFα in sarcoid lesions and to evaluate its role as a predictive marker in response to therapy with Remicade.

Material and methods: A total of 10 patients with newly diagnosed sarcoidosis were enrolled together with 10 control patients affected by rheumatoid arthritis. All patients were studied by planar imaging of the chest with (99m)Tc-infliximab at 6 h and 24 h and total body [(18)F]-FDG PET/CT. Regions of interest were drawn over the lungs and the right arm and target-to-background ratios were analysed for (99m)Tc-infliximab. SUV mean and SUV max were calculated over lungs for FDG.